To swab a barrel take an appropiate sized patch and get it damp with a solution. There aremany different solutions people use. Everything from water to about anything wet. Start the damp patch down the barrel working about 2" at a time, back and fourth. Then increase that to another 2" further down the barrel, working all the way to the breech. If you feel a hard spot it might take more scrubbing.

After you have reached the bottom, pull the patch and turn it upside down. Now work the damp patch again down the barrel in the same manner as before. After the damp patch, I like to run two dry patchs just like the damp one, a little at a time. When the dry patch comes out dry, the barrel is swabbed.

Swabbing will improve accuracy in a rifle. The necessity of swabbing will be determined by how hard the rifle loads, and how bad the accuracy becomes. With powders like APP, the need for swabbing is greatly reduced. In fact some people using APP do not swab at all. That decision is up to you. I would at least swab every fifth sabot load if working up a load with APP..